As with so many other advances it isn't possible to reach into someone's head (ugh) an change attitudes. It was NOT that long ago that a white worker could call a black one the n-word right in front of everyone with no fear of reprisal; now he will be escorted out of the building under guard.

Change the law, you change behavior. It may take a generation or two but attitudes will follow. Already the idea of opposing same-sex marriage is starting to seem just bigoted.

The charge of tokenism is inevitable, and complicated by the fact that a minority has to be superlative in the same role where a majority can be average.

It's also complicated by the fact that there really are people who think they're helping by promoting mediocrities above their level. The most uncontroversial example I can think of was Asimov's Science Fiction Magazine and its promotion of some truly awful women writers. There are some great women writing SF; LeGuin, Cherryh, others. ASFM printed some who were just awful, which did not help women writers one bit.